Related papers: Scattering Amplitudes in High Energy QCD
In these proceedings, I shall review the basic concepts of perturbative QCD in its high-energy limit, emphasising the approach to the unitarity limit, usually referred to as {\em saturation}. I shall explain the basic framework showing the…
Many search strategies for the Standard Model Higgs boson apply specific selection criteria on hadronic jets observed in association with the Higgs boson decay products, either in the form of a jet veto, or by defining event samples…
In this paper we show that the sum of enhanced BFKL Pomeron loop diagrams generates the scattering amplitude, which turns out to be much smaller, than in the case of deep inelastic scattering. We use the simplified BFKL kernel in the…
This work revisits the computation of six-gluon scattering amplitudes in the high energy limit of strongly coupled N=4 supersymmetric Yang-Mills theory. It is based on previous studies in which we showed that the amplitude simplifies in the…
A large theoretical uncertainty due to the choice of the top-quark mass renormalisation scheme is present in QCD predictions for Higgs boson pair production. In these proceedings, we report on the recent progress in tackling these…
The asymptotic behavior of the scattering amplitude for two scalar particles at high energies with fixed momentum transfers is studied. The study is done within the effective theory of quantum gravity based on quasi-potential equation. By…
We present an all-order generalized factorization formula for QCD scattering amplitudes in kinematical configurations where two or more momenta of the external partons become collinear. The singular behaviour of the scattering amplitudes in…
The inclusive production of jets in the central region of rapidity is studied in $k_T$-factorization at next-to-leading order (NLO) in QCD perturbation theory. Calculations are performed in the Regge limit making use of the NLO BFKL…
The procedure to improve the convergence in transverse momentum space of the NLL BFKL kernel using a w-shift is revisited. An accurate approximation to this shift only depending on transverse momenta is presented. This approximation is…
I describe how to calculate cross sections for hard-scattering processes in high energy collisions at next to leading order in QCD. I consider infrared-safe quantities and I assume that the scattering amplitudes are known in analytic form…
The one-loop QCD effective charge $\alpha_s^{eff}$ for quark-quark scattering is derived by diagrammatic resummation of the one-loop amplitude using an arbitary covariant gauge. Except for the particular choice of gauge parameter $\xi =…
$s$-channel discontinuity of quark-quark scattering amplitude with gluon quantum numbers in the $t$ channel and negative signature is calculated in the Regge kinematical region in the two-loop approximation. Using this discontinuity and…
We present an expression for the QCD amplitude for a general hard scattering process with any number of soft gluon emissions, to one-loop accuracy. The amplitude is written in two different but equivalent ways: as a product of operators…
I demonstrate that the amplitude for high-energy scattering can be factorized as a convolution of the contributions due to fast and slow fields. The fast and slow fields interact by means of Wilson-line operators -- infinite gauge factors…
We provide the last missing ingredient necessary to approximate one-loop amplitudes in QCD with massive quarks in the limit of vanishing energy of a single gluon up to terms suppressed by this energy. Our main result is a soft operator…
In this paper we proceed with the study of the Pomeron spectrum, by solving numerically the BFKL equation with massive gluons and running coupling. The spectrum of Regge singularities is discrete and the leading Pomeron has a considerable…
Contributions from gluon interactions, which are non-leading in high-energy semi-hard processes, are studied and represented in terms of reggeon exchanges. Unlike the leading gluonic reggeon, related to the BFKL pomeron, the non-leading…
We generalise the factorization of abelian gauge theory amplitudes to next-to-leading power (NLP) in a soft scale expansion, following a recent generalisation for Yukawa theory. From an all-order power counting analysis of leading and…
The Balitsky-Fadin-Kuraev-Lipatov (BFKL) approach for the cross sections at high energy $\sqrt s$ in perturbative QCD is briefly reviewed. The role of gluon Reggeization in the derivation of the BFKL equation and its compatibility with…
Studying semi-hard processes in the large center-of-mass energy limit gives us an opportunity to further test perturbative QCD in an unexplored kinematical configuration, contributing to a better understanding of the dynamics of strong…